Out-Pranked By Another Prank Master
by GoldGuardian2418
Summary: When Sans pulls some pranks on Underswap Papyrus, Orange gets back at him to teach him a ticklish lesson. Art trade done with capitalofawesome on DeviantArt. :)


**An art trade I've done for capitalofawesome on DeviantArt. Undertale belongs to Toby Fox. Underswap belongs to Popcorn Pr1nce** **on Tumbler. I only own Charlotte.**

 **A/N: To avoid confusion, I will use the nicknames Orange and Blue for Underswap Papyrus and Sans. Also, in this story, Frisk's prior experiences with Chara haven't been pleasant, so she and the others view Chara as evil (unlike my other stories where Chara was saved and found peace). The same is said for Underswap Chara and the Underswap skeletons who view Frisk as evil from their experiences** _ **.**_ **Just wanted to clear that up. :) Also, this story does contain spoilers.**

 **Now, on with the story! :)**

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 **Out-Pranked By Another Prank Master**

Frisk slid down the slide at the playground, giggling as she reached her arms out to the hoodie-wearing skeleton at the bottom of the slide, who smiled and reached his arms out, catching her at the end of the slide and lifting her up in the air, making her giggle again. "I'm going to go sit down for a bit, kiddo," he said, feeling a little winded. "How about Pap catches you for a bit?"

"Okay, Dunkle Sans," she said, knowing he was a bit tired as he had been working hard at his job and today was one of his days off and he had woken up early with Papyrus to take her to the playground as he had promised her. She now ran back for the other end of the jungle gym to get to the slides while Sans sat down on the bench to watch while his brother waited patiently by the end of the slide for Frisk.

The young, brown-eyed girl happily ran around and was about to climb up the steps when another girl came up behind her, eager to climb up too. Frisk would have continued, except she caught sight of a yellow and green sleeve and stopped, turning around quickly, her eyes widened as she let out a scream. The other child, Chara, let out a scream too and both girls ran away from each other, running towards opposite ends of the playground.

Hearing his niece scream, Sans instantly jumped up, calling up a Gaster Blaster and Papyrus quickly called up a long bone as Frisk came running up to them and grabbed onto Sans, clinging tightly. "What happened, kiddo?" He asked, keeping his voice level despite being on alert.

"I-I s-saw Ch-Chara," Frisk whimpered.

Both skeletons froze. "Are you sure, Frisk?" Papyrus asked.

She nodded. "She was right behind me," she whimpered. "But she screamed and ran off when I did."

Sans grew thoughtful. "That's not how she acted before," he said. "Where did she run off to?"

Frisk pointed behind her. "That way," she said.

Both brothers moved cautiously, coming around the jungle gym and stopped short as they came face to face with two more skeletons, who stopped short as well. Chara was in the arms of a skeleton that looked just like Papyrus, but was dressed like Sans, while a short skeleton who looked just like Sans but was dressed like Papyrus looked at them in surprise. Chara, seeing Frisk, whimpered and clung to the tall skeleton while Frisk clung to Sans, whose left eye was now lit up with his power. The Papyrus look-alike snapped his fingers to call up a Gaster Blaster and both his eyes lit up orange while the Sans look-alike called up a long bone, but looked rather reluctant about it.

The four skeletons stared at each other, not moving for a bit before a flash caught their attention and they turned to find a familiar woman walking towards them and she looked relieved. "Whew! Looks like perfect timing," she said.

"Charlotte?" Sans asked in surprise.

"Hey, Sans. Hey, Papyrus. Hey, Frisk," she greeted them.

"Miss Charlotte? You know them?" The Sans look-alike asked, his voice hopeful.

She smiled at him. "Yes, I do, Blue," she said before looking confused. "But…why are you and Orange looking ready to battle as Sans and Papyrus are?"

"We heard Chara scream and she came running to us saying she saw Frisk," the Papyrus look-alike said, holding the small child in a comforting hug.

Charlotte then turned to the other two, who looked a bit confused at why Chara was acting frightened like Frisk was. "Frisk screamed too and came running to us saying she saw Chara," Sans clarified.

The young author took a moment before her eyes widened in realization and she took a deep breath and let it out slowly. "Guys, relax," she said. "It's just a misunderstanding."

Looking unsure, the four skeletons relaxed and let their magics dissipate. Charlotte decided on introductions. "Sans. Papyrus, these three are from the alternate universe knows as Underswap," she explained. "In that universe, personalities are switched between the inhabitants. Papyrus and Sans would have swapped personalities as would Chara and Frisk. For example, Sans is trying to get into the Royal Guard and Papyrus is the one to first meet the human outside the Ruins. Chara is the one who falls down in the Underground and goes to free the monsters while Frisk is the evil spirit that tries to hurt Chara."

The brown-haired woman now turned to the three from Underswap. "In the original universe, Papyrus is going for the Royal Guard while Sans is the sentry and Frisk is the one to break the barrier and Chara is the evil spirit," she continued. "The girls must have thought each other was the evil spirit, which is why they're both frightened."

Papyrus was first to react and reached his hand out towards Blue. "I'm always glad to meet another Royal Guard trainee," he said in a friendly voice.

Blue lit up at that. "Maybe we can train together," he suggested brightly.

Seeing their brothers becoming fast friends, the other two skeletons relaxed and Sans extended his hand. "Sorry about the rough start," he said. "My bro and I are really protective of Frisk and sometimes _jump the gun,_ as humans say."

Orange chuckled, extending his own hand. "My brother and I are the same way with Chara," he said as they clasped hands and to both their surprises, whoopee cushions sounded out right then. Charlotte burst into laughter at that while Blue and Papyrus looked a bit annoyed. Frisk and Chara both began giggling before the two skeletons set the girls down and had them face each other. Chara shied back a little, not really wanting to leave the safety of her uncle's arms, something that Frisk understood and it made her feel a bit bad that she had scared the other girl without meaning to. She looked at Sans, who nodded encouragingly and gave her a gentle nudge forward. Reassured, she moved towards Chara and extended her hand for a handshake. The red-eyed girl looked at her warily before looking up at Orange, who gave her an encouraging nod. "Go ahead," he whispered gently to her so only she heard him.

Swallowing, she took a small step and reached for Frisk's hand, biting her lip nervously as their hands met and Frisk gently shook Chara's hand. The red-eyed girl relaxed at that and saw that the other girl didn't look mean as the evil spirit she knew. "Want to go play on the jungle gym?" The brown-eyed girl asked kindly.

Sans was proud of his niece for making friends with the other child and inviting her to play. He got a feeling Chara didn't get invited to play a lot by other kids. Orange nodded his consent when his niece looked up at him hopefully and the two children ran for the jungle gym together. Charlotte smiled and waved before disappearing into another portal for her home while Blue and Papyrus decided to go do some training nearby, leaving Orange and Sans to go watch the children, who now seemed quite at ease and playing happily. "You've got a good kid, Sans," Orange said. "She's actually the first human to be nice to Chara."

The blue hoodie-wearing skeleton blinked. "Seriously?" He asked in surprise. "Chara…doesn't have any friends besides you guys?"

The tall skeleton shook his head. "They make fun of her because of her eyes," he said. "And whenever she's tried to make friends on the surface, the parents snatch their kids away and drive her off, calling her derogatory names."

Even though he didn't know the kid that well, Sans felt pity for the red-eyed girl. "Frisk has had the same problem," he admitted. "She gets bullied a lot for being the kid that helped us get back to the surface and we've had some of her teachers even bullying her."

Orange shook his head. "That's sad," he said with a sigh.

"Tell me about it," Sans said, also sighing.

Frisk and Chara suddenly came running towards them. "Can you push us on the swings?" Chara asked hopefully.

Both skeletons checked the time and Sans looked thoughtful. "Pap's got a meeting with Undyne in a bit, so we'll have to leave soon," he said to Frisk, who nodded understandingly and then looked at Chara and Orange hopefully.

"Could Chara come over and play at our house?" She asked, looking at her dunkle with large, brown eyes.

Sans gently chuckled. "You use those puppy eyes too often, kiddo," he said half-seriously, but smiled and turned to Orange. "Would you, your brother, and Chara like to come over to our place?"

The tall skeleton smiled. "Sure," he said, to which Chara gave a happy squeal. "Just curious, who's Undyne?"

"She was Captain of the Royal Guard in the Underground," the shorter skeleton explained. "She still trains with Papyrus, but it's mostly for the police force, which she just made detective."

"She sounds just like our Alphys," Orange said. "She joined the police force too and is looking to be a detective."

"Cool," Sans said as they now all headed for Sans and Papyrus' home, stopping at Undyne's house to say hello and Papyrus stayed with her. Blue was interested to see what Undyne could teach him and so Orange asked Undyne if Blue could join in training too. The fish woman welcomed the new skeleton instantly, hardly batting an eye at how Blue looked like Sans, and liking the fact that Blue had the same eagerness Papyrus had.

Frisk and Chara ran up ahead, skipping happily and jumping over the cracks in the sidewalk, making it into a game while Sans and Orange walked a little behind the girls, both chuckling. "Chara's a good kid," Sans said suddenly. "I haven't seen any other human children reach out to be Frisk's friend. And the best part is Chara understands because she's got you guys as family."

Orange nodded. "Yes," he said. "I was just thinking the same thing about Frisk."

He suddenly moved forward and caught Chara, lifting her up in the air playfully, to which she giggled happily as he set her on his shoulders and she quickly locked her hands under his chin. Sans smiled and snapped his fingers, catching Frisk in his telekinesis and making her giggle before he placed her on his back and she instantly clung to him while he hooked his hands around her knees to keep her in place as they made it to the house and went inside.

While the two girls played upstairs, Sans secretly set up some of his pranks to prank Orange, who was in the living room. Learning he liked honey, Sans found some and placed some ketchup in the honey bottle. Not a lot, but enough to be instantly tasted when the other drank it.

Sure enough, tasting the ketchup, Orange lurched forward in surprise, his eyes wide as he opened the cap to the honey and found the ketchup on top of the sweet substance. Sans had a hard time holding in his snickers, but just managed it while Orange recovered from the prank.

But Sans didn't stop there. He put a whoopee cushion in a chair where Orange later sat, setting off the prank, and he put whipped cream onto the taller skeleton's hand while he slept and then sneakily traced a feather over the sleeping skeleton's face, making Orange slap at his face to stop the irritating feather and getting a face full of whipped cream instead, making Sans burst into laughter before he tried a new prank he had seen some people pulling on each other.

It was the penny and the water bottle trick and when Orange leaned down to look, the shorter skeleton quickly squeezed the water bottle, making it squirt the taller skeleton, who stumbled back in alarm before taking a moment and wiping the water off his skull and looking up in time to see Sans disappear from the room by teleporting.

"Four pranks in a row," Orange said to himself before standing taller. "I think it's time the tables got turned on him."

He found Chara and Frisk playing a video game in Frisk's room and they paused the game when he gently cleared his throat to get their attention. "Frisk, I was curious about something," he said.

"Yes, Uncle Orange?" She asked, surprising him a little with that, but saw Chara smile, which meant she was glad Frisk saw him as an uncle like she did.

"Is your dunkle ticklish by chance?"

Frisk grinned and nodded. "His ribs," she said. "And feet."

The tall skeleton smiled. "I see," he said.

The brown-eyed girl tilted her head curiously. "Why?" She asked.

Orange smiled. "Your dunkle decided to prank me," he said. "Four times."

Frisk giggled at that. "He does that a lot to Uncle Papyrus," she said.

"Well, I aim to return the favor," the orange hoodie-wearing skeleton said. "Where would he be now, do you think?"

"I think his room," the young girl said.

Nodding, Orange left them to their video game while he found Sans' room and snapped his fingers, activating his magic and opening the door softly. Seeing Sans' back was to him, he reached out his right hand.

Feeling a strange pull, Sans glanced up and was too late to activate his telekinesis as Orange came in, closing the door and strengthening his telekinetic hold on the shorter skeleton, placing him on the messy bed. Sans gulped as he saw the devious look on the taller one's face. "Four times you've pranked me," he said to the trapped skeleton. "I'm going to return the favor, Sans. Do you know how?"

The shorter skeleton shook his head and Orange smiled. "By using four different tickle tools on you in a tickle torture you're not going to forget anytime soon," he said. "My hands, a soft brush, feathers, and an electric toothbrush."

Sans gulped again. "Hey, Orange, you don't have to do that," he said nervously. "How about I don't prank you again and we'll call a truce?"

The tall skeleton smiled, but shook his head. "Nope, you're not getting out of this that easily," he said. "You need to be taught a lesson about pranking another prank master and that's what I aim to do."

Sans knew he was in big trouble, because from what Charlotte had said, both he and Orange shared the same personality, which meant the taller skeleton would no doubt be a master tickler, especially if he just listed off the tools he was going to use. Orange made sure his telekinesis held his victim well while he moved the white shirt up to reveal the sensitive ribcage and his fingers instantly went to work.

"AHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA!" Sans belted out as his number one tickle spot was mercilessly assaulted by Orange's skillful fingers, shrieking loud enough to make the windows rattle when the taller skeleton began tickling the lower ribs that didn't connect to the ribcage. "EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE!"

Orange chuckled. "If you react like that to just my fingers, I can't wait to see your reaction with the other tools I'm going to use on you," he said gleefully as he paused a moment to allow his victim a breather. "Now, how about your feet?"

The trapped skeleton tried to struggle as his captor went for his other tickle spot. "No! Don't!" He pleaded.

"You haven't learned your lesson yet," the tall skeleton said with a chuckle as he began tickling the helpless skeleton's feet. "Tickle, tickle, tickle! What a ticklish skeleton!"

Oh, he knew how to use the teasing words to make the tickle torture worse and Sans would have no doubt jumped out of his skin if he had skin when Orange's fingers began tickling his toes, not missing one spot.

Thankfully, after a few minutes, the winded skeleton was granted another breather and he gasped for air while Orange took a moment to decide which tool he wanted to use and picked out the electric toothbrush, showing it to Sans, who let out a fearful whine and began struggling again, but the orange telekinesis held him firmly as his captor turned on the electric toothbrush and brought it down carefully to Sans' ribs.

The scrubbing of the toothbrush head along with the vibrations proved to be worse than Orange's fingers and Sans arched his back as he let out the loudest unmanly shriek before dissolving into laughter again.

"AHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA! NOHOHOHOHOHOHOHOHOHOHOHO! HEHEHEHEHEHELP!" He cried out.

"You're not going to escape," Orange said, smiling down at his laughing victim. "You still haven't learned your lesson fully."

"ORAAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHANGE! PLEHEEHEEHEEHEEHEEHEEHEEHEEASE!"

The tall skeleton chuckled. "Cootchie, cootchie, coo!" He cooed, getting each of Sans' ribs good before moving over to Sans' feet again and running the tickle tool all over the sensitive foot and the wiggling toes. "Look at those little toes wiggle! They're so ticklish! You're so ticklish!"

Sans couldn't speak now as he was reduced to laughing so hard it seemed as though tickle paralysis had taken hold of him and he could barely squirm, something that his captor noticed and pulled back a little of his telekinesis while he turned off the electric toothbrush, putting it away as his victim lay there, panting for air and looking relieved. "If you think the tickle torture is over, you're wrong," Orange said, bursting Sans' hope like a bubble and making the short skeleton give him a pleading look. "But I'll give you something to regain your strength."

He pulled out some monster candy and unwrapped it, holding the candy to Sans' mouth and the skeleton opened his mouth, eating the candy gratefully and feeling better, but giving him a forlorn look. "Come on, Orange," he said pleadingly. "Let's just call it even, huh, buddy?"

The taller skeleton shook his head. "You still have two more pranks to atone for," he said. "You've learned your lesson halfway. You need to learn it the whole way."

Seeing Sans look a bit scared, Orange gently rubbed the shorter skeleton's skull in a comforting manner. "I'll let you rest a bit more before we continue," he said comfortingly. "By the way, why do you like ketchup so much?"

"Why do you like honey so much?" Sans countered.

His captor smiled. "Fair enough," he said. After a few moments of silence, he stood up and brought out a soft brush. "Time to continue."

The brush just barely touched the ticklish ribs, which were still tingling a little and more sensitive from the tickles, but it might as well have fully touched them because Sans jumped a good three inches off the bed with another unmanly shriek and laughing louder as the brush scrubbed gently all over his ribs before his feet were tickle tortured by the brush. Tears actually budded around Sans' eyes now from the intensity of the soft brush tickling his feet all over mercilessly.

Satisfied for now, Orange put the brush away. "Three down, one more to go," he said. "I can see you've almost completely learned your lesson, therefore you've earned yourself a longer breather before I bring out the feathers."

The shorter skeleton couldn't talk as he was gasping for air, rubbing the sides of his face on his pillow to wipe away the tears that had gathered in his eyes. He felt something being gently pressed to his mouth again and saw it was more monster candy, which he gratefully ate before feeling the taller skeleton rub his head again in a soothing manner. "Don't worry," he said. "Just one more round with the feathers and it'll be over."

Sans just lay there. "Charlotte was right," he said. "You do have my exact personality. And it a little _unnerving."_

"I find it a little unnerving that you have the exact same tickle spots I do," Orange said. "Chara's gotten me more than once as has Blue."

"Pap and Frisk have gotten me more than once too," Sans admitted.

The tall skeleton chuckled and then pulled out a long feather. "Now then, shall we finish this up?" He asked.

The one thing Sans hated on his tickle spots were feathers because they tickled all over worse than anything else and he let out a whimper of fear. "Orange, please?" He tried to plead.

"Sorry, Sans," he said. "But you have one more prank to atone for."

The feather inched closer to the sensitive ribs and without warning, Orange ran the feather in quick, precise strokes over his victim's ribcage.

Sans' reaction was the loudest, unmanly squeal ever heard, a squeal that made the windows rattle and the walls shake as he was tickled mercilessly with that feather that his captor expertly stroked over each rib inside and outside, stroking the feather over the lower, unconnected ribs well and then going over to the wiggling feet and toes, which wiggled more desperately when tickled by the soft feather.

"AHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA!"

Orange smiled at his victim's laughter. "Cootchie, cootchie, coo!" He cooed. "Has this little skeleton learned his lesson? Hmm? Tickle, tickle, tickle, tickle!"

The trapped skeleton was now desperate to escape and feeling very tired. "Orahahahange," he managed to rasp out through his dying laughter, something the tall skeleton took note of and stopped, snapping his fingers to dispel his telekinesis and allow Sans to move, but the panting skeleton couldn't move even his little finger as he lay there tiredly, looking up at his friend. "You got me good," he said, weakly holding out a hand to shake and concede that he had been pranked good by the taller skeleton.

Orange shook his hand with a smile before scooping him up in his arms. "You act so much like Blue after I've tickled him to pieces," he said.

Sans weakly laughed, not minding that the taller skeleton was carrying him out to the living room. The girls were in Frisk's room, but had apparently worn themselves out to where they were passed out on the floor, making the two smile as Orange gently lifted them up with his telekinesis and Sans motioned to the guest bedroom nearby. "The bed in there's large enough for all of us," he said. "I'm _bone-tired."_

The tall skeleton chuckled as he set Sans down on one side of the bed and placed Frisk and Chara beside him before going over and laying down on the other side so that the children were between them. Chara turned in her sleep and snuggled into Orange's chest, making him smile as he wrapped a protective arm around her and Sans did the same with Frisk before they fell fast asleep, which was how their brothers found them later on, but let them be, smiling to each other.

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 **Please leave a review, but no flames!**

 **GoldGuardian2418**


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